[docs] Update ES2015 features allowed in Chromium code
Update the examples to prefer `const` over `let` or `var`, per the Google JavaScript style guide [1]. Also update the spec links to point to the latest available draft [2] instead of a versioned snapshot, since that’s what we aim to implement. [1] https://google.github.io/styleguide/jsguide.html [2] https://tc39.github.io/ecma262/ Change-Id: If019e533a1aa320fefe02185c64fe1b632e26c81 Reviewed-on: https://chromium-review.googlesource.com/c/1122220 Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org> Commit-Queue: Mathias Bynens <mathias@chromium.org> Cr-Commit-Position: refs/heads/master@{#599536}
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@ -14,7 +14,7 @@
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hyphen-hyphen-hyphen (change to actual hyphen)
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-->
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<style type="text/css">
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<style>
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.doc {
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font-size: 16px;
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}
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@ -58,12 +58,12 @@ hyphen-hyphen-hyphen (change to actual hyphen)
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document.addEventListener('DOMContentLoaded', function(event) {
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// Move all headers and corresponding contents to an accordion container.
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document.querySelectorAll('h2[id]').forEach(function(header) {
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var container = document.createElement('div');
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const container = document.createElement('div');
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container.classList.add('feature-container');
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header.parentNode.insertBefore(container, header);
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// Add all the following siblings until it hits an <hr>.
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var el = header;
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let el = header;
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while (el && el.tagName !== 'HR') {
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var nextEl = el.nextElementSibling;
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container.append(el);
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@ -85,12 +85,13 @@ document.addEventListener('DOMContentLoaded', function(event) {
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[TOC]
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# ES6 Support In Chromium
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# ES2015 Support In Chromium
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This is a list of [ECMAScript6](https://developer.mozilla.org/en-US/docs/Web/JavaScript/New_in_JavaScript/ECMAScript_6_support_in_Mozilla)
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This is a list of [ECMAScript 6 a.k.a.
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ES2015](https://developer.mozilla.org/en-US/docs/Web/JavaScript/New_in_JavaScript/ECMAScript_6_support_in_Mozilla)
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features allowed in Chromium code.
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This is **not** a status list of [v8](https://developers.google.com/v8/)'s
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This is **not** a status list of [V8](https://developers.google.com/v8/)'s
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support for language features.
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> **TBD:** Do we need to differentiate per-project?
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@ -103,8 +104,9 @@ you think it should or should not be allowed, along with links to any relevant
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previous discussion. If the list arrives at some consensus, send a codereview
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to change this file accordingly, linking to your discussion thread.
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> Some descriptions and Usage examples are from [kangax](https://kangax.github.io/compat-table/es6/)
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and [http://es6-features.org/](http://es6-features.org/)
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> Some descriptions and usage examples were taken from
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> [kangax](https://kangax.github.io/compat-table/es6/)
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> and [http://es6-features.org/](http://es6-features.org/)
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# Allowed Features
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@ -139,12 +141,12 @@ window.addEventListener('scroll', (event) => {
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() => {return 1;} // returns 1.
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```
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**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-arrow-function-definitions)
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**Documentation:** [link](https://tc39.github.io/ecma262/#sec-arrow-function-definitions)
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**Discussion Notes / Link to Thread:**
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**Note**: => does not work in iOS9. Don't use it in code that runs on Chrome for
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iOS. There's a presubmit that should warn you about this.
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iOS. There's a presubmit check that should warn you about this.
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[Discussion thread](https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/iJrC4PVSfoU)
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@ -159,7 +161,7 @@ value which may be available now, or in the future, or never.
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```js
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/** @type {!Promise} */
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var fullyLoaded = new Promise(function(resolve) {
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const fullyLoaded = new Promise(function(resolve) {
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function isLoaded() { return document.readyState == 'complete'; }
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if (isLoaded()) {
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@ -175,7 +177,7 @@ var fullyLoaded = new Promise(function(resolve) {
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fullyLoaded.then(startTheApp).then(maybeShowFirstRun);
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```
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**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-promise-objects)
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**Documentation:** [link](https://tc39.github.io/ecma262/#sec-promise-objects)
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[link](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise)
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**Discussion Notes:** Feature already extensively used prior to creation of
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@ -197,7 +199,7 @@ class Shape {
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this.y = y;
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}
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}
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// Note: let Shape = class {...}; is also valid.
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// Note: const Shape = class {...}; is also valid.
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class Rectangle extends Shape {
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constructor(x, y, width, height) {
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@ -207,13 +209,13 @@ class Rectangle extends Shape {
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}
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static goldenRectangle() {
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var PHI = (1 + Math.sqrt(5)) / 2;
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const PHI = (1 + Math.sqrt(5)) / 2;
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return new Rectangle(0, 0, PHI, 1);
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}
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}
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```
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**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-class-definitions)
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**Documentation:** [link](https://tc39.github.io/ecma262/#sec-class-definitions)
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**Discussion Notes / Link to Thread:**
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https://groups.google.com/a/chromium.org/d/msg/chromium-dev/S1h-0m2ohOw/jyaiMGDlCwAJ
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@ -232,11 +234,11 @@ may be used as either a key or a value.
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**Usage Example:**
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```js
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var map = new Map();
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const map = new Map();
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map.size === 0; // true
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map.get('foo'); // undefined
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var key = 54;
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const key = 54;
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map.set(key, 123);
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map.size === 1; // true
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map.has(key); // true
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@ -247,7 +249,7 @@ map.has(key); // false
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map.size === 0; // true
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```
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**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-map-objects)
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**Documentation:** [link](https://tc39.github.io/ecma262/#sec-map-objects)
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[link](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map)
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**Discussion Notes:** Feature already extensively used prior to creation of
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@ -263,7 +265,7 @@ values or object references.
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**Usage Example:**
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```js
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var set = new Set();
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const set = new Set();
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set.add(123);
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set.size(); // 1
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@ -273,7 +275,7 @@ set.add(123);
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set.size(); // 1
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```
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**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-set-objects)
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**Documentation:** [link](https://tc39.github.io/ecma262/#sec-set-objects)
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[link](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set)
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**Discussion Notes:** Feature already extensively used prior to creation of
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@ -281,15 +283,46 @@ this document.
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---
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## let (Block-Scoped Variables)
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## const (Block-Scoped Constants)
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`let` declares a variable within the scope of a block. This differs from `var`,
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which uses function level scope.
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Constants (also known as "immutable variables") are variables which cannot be
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re-assigned new content. Note that if the value is an object, the object itself
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is still mutable.
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`const` is block-scoped, just like `let`.
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**Usage Example:**
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```js
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const gravity = 9.81;
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gravity = 0; // TypeError: Assignment to constant variable.
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gravity === 9.81; // true
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const frobber = {isFrobbing: true};
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frobber = {isFrobbing: false}; // TypeError: Assignment to constant variable.
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frobber.isFrobbing = false; // Works.
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```
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**Documentation:** [link](https://tc39.github.io/ecma262/#sec-let-and-const-declarations)
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**See also:** [Object.freeze()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/freeze)
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**Discussion Notes / Link to Thread:** [link](https://groups.google.com/a/chromium.org/d/msg/chromium-dev/MJhTok8Usr8/XCrkisaBBQAJ)
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**Note**: `const` [not fully supported](https://caniuse.com/#feat=let) in iOS9.
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Don't use it in code that runs on Chrome for iOS, until support for iOS9 is
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dropped.
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---
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## let (Block-Scoped Variables)
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`let` declares a variable within the scope of a block, like `const`.
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This differs from `var`, which uses function-level scope.
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**Usage Example:**
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```js
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// Scope.
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function varTest() {
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var x = 1;
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if (true) {
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@ -318,7 +351,7 @@ function f() {
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}
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```
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**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-let-and-const-declarations)
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**Documentation:** [link](https://tc39.github.io/ecma262/#sec-let-and-const-declarations)
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**Discussion Notes / Link to Thread:** [link](https://groups.google.com/a/chromium.org/d/msg/chromium-dev/MJhTok8Usr8/XCrkisaBBQAJ)
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@ -328,46 +361,14 @@ dropped.
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---
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## const (Block-Scoped Constants)
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Constants (also known as "immutable variables") are variables which cannot be
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re-assigned new content. Note that if the value is an object, the object itself
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is still mutable.
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Also note that in Chrome, `const` is block scoped like `let`.
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**Usage Example:**
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```js
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const gravity = 9.81;
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gravity = 0; // TypeError: Assignment to constant variable.
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gravity === 9.81; // true
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const frobber = {isFrobbing: true};
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frobber = {isFrobbing: false}; // TypeError: Assignment to constant variable.
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frobber.isFrobbing = false; // Works.
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```
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**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-let-and-const-declarations)
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**See also:** [Object.freeze()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/freeze)
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**Discussion Notes / Link to Thread:** [link](https://groups.google.com/a/chromium.org/d/msg/chromium-dev/MJhTok8Usr8/XCrkisaBBQAJ)
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**Note**: `const` [not fully supported](https://caniuse.com/#feat=let) in iOS9.
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Don't use it in code that runs on Chrome for iOS, until support for iOS9 is
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dropped.
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---
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## Array Static & Prototype Methods
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**Usage Example:**
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```js
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// Static methods
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let a1 = Array.from(document.querySelectorAll('div'));
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let a2 = Array.of(7);
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const a1 = Array.from(document.querySelectorAll('div'));
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const a2 = Array.of(7);
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// Prototype methods
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['a', 'b', 'c', 'd'].copyWithin(2, 0); // Returns ['a', 'b', 'a', 'b']
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@ -379,12 +380,10 @@ let a2 = Array.of(7);
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[2, 4, 6, 8].entries(); // Returns an Array iterator
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```
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**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-properties-of-the-array-constructor)
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**Documentation:** [link](https://tc39.github.io/ecma262/#sec-properties-of-the-array-constructor)
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**Discussion Notes / Link to Thread:** [link](https://groups.google.com/a/chromium.org/d/msg/chromium-dev/d_2zUYQZJTg/-_PSji_OAQAJ)
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**Note**: `Array.prototype.values` is [not implemented in Chrome](https://kangax.github.io/compat-table/es6/#test-Array.prototype_methods) and should not be used. If the code in question is Closure compiled, a compile-time error will be thrown.
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---
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## Number Properties
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@ -401,7 +400,7 @@ let a2 = Array.of(7);
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// Number.MAX_SAFE_INTEGER
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```
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**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-isfinite-number)
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**Documentation:** [link](https://tc39.github.io/ecma262/#sec-isfinite-number)
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**Discussion Notes / Link to Thread:** [link](https://groups.google.com/a/chromium.org/d/msg/chromium-dev/d_2zUYQZJTg/-_PSji_OAQAJ)
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@ -426,7 +425,7 @@ Object.is(-0, +0) // false, btw: -0 === +0 is true
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```
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**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-properties-of-the-object-constructor)
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**Documentation:** [link](https://tc39.github.io/ecma262/#sec-properties-of-the-object-constructor)
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**Discussion Notes / Link to Thread:** [link](https://groups.google.com/a/chromium.org/d/msg/chromium-dev/d_2zUYQZJTg/-_PSji_OAQAJ)
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@ -435,19 +434,19 @@ Object.is(-0, +0) // false, btw: -0 === +0 is true
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## for...of Loops
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Convenient operator to iterate over all values in an iterable collection. This
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differs from `for ...in`, which iterates over all enumerable properties of an
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differs from `for...in`, which iterates over all enumerable properties of an
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object.
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**Usage Example:**
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```js
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// Given an iterable collection of Fibonacci numbers...
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for (let n of fibonacci) {
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for (const n of fibonacci) {
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console.log(n); // 1, 1, 2, 3, ...
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}
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```
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**Documentation:** [link1](http://www.ecma-international.org/ecma-262/6.0/#sec-for-in-and-for-of-statements)
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**Documentation:** [link1](https://tc39.github.io/ecma262/#sec-for-in-and-for-of-statements)
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[link2](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...of)
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**Discussion Notes / Link to Thread:** [link](https://groups.google.com/a/chromium.org/d/msg/chromium-dev/d_2zUYQZJTg/-_PSji_OAQAJ)
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@ -463,17 +462,17 @@ pieces.
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```js
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// Simple example
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let greeting = 'hello';
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let myName = {first: 'Foo', last: 'Bar'};
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let from = 1900;
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let to = 2000;
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const greeting = 'hello';
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const myName = {first: 'Foo', last: 'Bar'};
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const from = 1900;
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const to = 2000;
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var message = `${greeting}, I am ${myName.first}${myName.last},
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and I am ${to - from} years old`;
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// message == 'hello,\nI am FooBar,\nand I am 100 years old'
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```
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**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-template-literals)
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**Documentation:** [link](https://tc39.github.io/ecma262/#sec-template-literals)
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**Discussion Notes / Link to Thread:**
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@ -509,7 +508,7 @@ sections.
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}
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```
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**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-functiondeclarationinstantiation)
|
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**Documentation:** [link](https://tc39.github.io/ecma262/#sec-functiondeclarationinstantiation)
|
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|
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**Discussion Notes / Link to Thread:**
|
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|
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@ -539,7 +538,7 @@ hide(document.body); // Animated, animate=true by default.
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hide(document.body, false); // Not animated.
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```
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**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-functiondeclarationinstantiation)
|
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**Documentation:** [link](https://tc39.github.io/ecma262/#sec-functiondeclarationinstantiation)
|
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[link](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Default_parameters)
|
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|
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**Discussion Notes / Link to Thread:**
|
||||
@ -562,7 +561,7 @@ function usesRestParams(a, b, ...theRest) {
|
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usesRestParams('a', 'b', 1, 2, 3);
|
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```
|
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|
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**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-function-definitions)
|
||||
**Documentation:** [link](https://tc39.github.io/ecma262/#sec-function-definitions)
|
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|
||||
**Discussion Notes / Link to Thread:**
|
||||
|
||||
@ -577,15 +576,15 @@ function parameters.
|
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|
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```js
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// Spreading an Array
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var params = ['hello', true, 7];
|
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var other = [1, 2, ...params]; // [1, 2, 'hello', true, 7]
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const params = ['hello', true, 7];
|
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const other = [1, 2, ...params]; // [1, 2, 'hello', true, 7]
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|
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// Spreading a String
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var str = 'foo';
|
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var chars = [...str]; // ['f', 'o', 'o']
|
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const str = 'foo';
|
||||
const chars = [...str]; // ['f', 'o', 'o']
|
||||
```
|
||||
|
||||
**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-argument-lists-runtime-semantics-argumentlistevaluation)
|
||||
**Documentation:** [link](https://tc39.github.io/ecma262/#sec-argument-lists-runtime-semantics-argumentlistevaluation)
|
||||
|
||||
**Discussion Notes / Link to Thread:**
|
||||
|
||||
@ -599,21 +598,21 @@ Convenient new ways for object property definition.
|
||||
|
||||
```js
|
||||
// Computed property name
|
||||
var prop = 'foo';
|
||||
var o = {
|
||||
const prop = 'foo';
|
||||
const o = {
|
||||
[prop]: 'hey',
|
||||
['b' + 'ar']: 'there',
|
||||
};
|
||||
console.log(o); // {foo: 'hey', bar: 'there'}
|
||||
|
||||
// Shorthand property
|
||||
var foo = 1;
|
||||
var bar = 2;
|
||||
var o = {foo, bar};
|
||||
const foo = 1;
|
||||
const bar = 2;
|
||||
const o = {foo, bar};
|
||||
console.log(o); // {foo: 1, bar: 2}
|
||||
|
||||
// Method property
|
||||
var clearSky = {
|
||||
const clearSky = {
|
||||
// Basically the same as clouds: function() { return 0; }.
|
||||
clouds() { return 0; },
|
||||
color() { return 'blue'; },
|
||||
@ -622,7 +621,7 @@ console.log(clearSky.color()); // 'blue'
|
||||
console.log(clearSky.clouds()); // 0
|
||||
```
|
||||
|
||||
**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-object-initialiser)
|
||||
**Documentation:** [link](https://tc39.github.io/ecma262/#sec-object-initialiser)
|
||||
[link](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Object_initializer)
|
||||
|
||||
**Discussion Notes / Link to Thread:**
|
||||
@ -638,7 +637,7 @@ console.log(clearSky.clouds()); // 0
|
||||
0o767 === 503;
|
||||
```
|
||||
|
||||
**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-literals-numeric-literals)
|
||||
**Documentation:** [link](https://tc39.github.io/ecma262/#sec-literals-numeric-literals)
|
||||
|
||||
**Discussion Notes / Link to Thread:**
|
||||
|
||||
@ -652,7 +651,7 @@ console.log(clearSky.clouds()); // 0
|
||||
'𠮷'.match(/./u)[0].length === 2;
|
||||
```
|
||||
|
||||
**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-get-regexp.prototype.sticky)
|
||||
**Documentation:** [link](https://mathiasbynens.be/notes/es6-unicode-regex)
|
||||
|
||||
**Discussion Notes / Link to Thread:**
|
||||
|
||||
@ -666,7 +665,7 @@ console.log(clearSky.clouds()); // 0
|
||||
'\u{1d306}' == '\ud834\udf06'; // true
|
||||
```
|
||||
|
||||
**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-literals-string-literals)
|
||||
**Documentation:** [link](https://mathiasbynens.be/notes/javascript-unicode#escape-sequences)
|
||||
|
||||
**Discussion Notes / Link to Thread:**
|
||||
|
||||
@ -701,10 +700,10 @@ Flexible destructuring of collections or parameters.
|
||||
|
||||
```js
|
||||
// Array
|
||||
var [a, , b] = [1, 2, 3]; // a = 1, b = 3
|
||||
const [a, , b] = [1, 2, 3]; // a = 1, b = 3
|
||||
|
||||
// Object
|
||||
var {width, height} = document.body.getBoundingClientRect();
|
||||
const {width, height} = document.body.getBoundingClientRect();
|
||||
// width = rect.width, height = rect.height
|
||||
|
||||
// Parameters
|
||||
@ -725,7 +724,7 @@ h({name: 'bar', val: 42});
|
||||
|
||||
```
|
||||
|
||||
**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-destructuring-assignment)
|
||||
**Documentation:** [link](https://tc39.github.io/ecma262/#sec-destructuring-assignment)
|
||||
|
||||
**Discussion Notes / Link to Thread:**
|
||||
|
||||
@ -744,11 +743,10 @@ export function getArea() {...};
|
||||
export {width, height, unimportant};
|
||||
|
||||
// app.js
|
||||
import {getArea, width, height} from 'lib/rect';
|
||||
|
||||
import {getArea, width, height} from './lib/rect.js';
|
||||
```
|
||||
|
||||
**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-modules)
|
||||
**Documentation:** [link](https://developers.google.com/web/fundamentals/primers/modules)
|
||||
|
||||
**Discussion Notes / Link to Thread:**
|
||||
|
||||
@ -766,7 +764,7 @@ const foo = Symbol();
|
||||
const bar = Symbol();
|
||||
typeof foo === 'symbol'; // true
|
||||
typeof bar === 'symbol'; // true
|
||||
let obj = {};
|
||||
const obj = {};
|
||||
obj[foo] = 'foo';
|
||||
obj[bar] = 'bar';
|
||||
JSON.stringify(obj); // {}
|
||||
@ -775,7 +773,7 @@ Object.getOwnPropertyNames(obj); // []
|
||||
Object.getOwnPropertySymbols(obj); // [foo, bar]
|
||||
```
|
||||
|
||||
**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-symbol-constructor)
|
||||
**Documentation:** [link](https://tc39.github.io/ecma262/#sec-symbol-constructor)
|
||||
|
||||
**Discussion Notes / Link to Thread:**
|
||||
|
||||
@ -797,7 +795,7 @@ Object.getOwnPropertySymbols(obj); // [foo, bar]
|
||||
// String.prototype.includes
|
||||
```
|
||||
|
||||
**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-properties-of-the-string-constructor)
|
||||
**Documentation:** [link](https://tc39.github.io/ecma262/#sec-properties-of-the-string-constructor)
|
||||
|
||||
**Discussion Notes / Link to Thread:**
|
||||
|
||||
@ -808,7 +806,7 @@ Object.getOwnPropertySymbols(obj); // [foo, bar]
|
||||
**Usage Example:**
|
||||
|
||||
```js
|
||||
let fibonacci = {
|
||||
const fibonacci = {
|
||||
[Symbol.iterator]() {
|
||||
let pre = 0, cur = 1;
|
||||
return {
|
||||
@ -841,13 +839,13 @@ function* range(start, end, step) {
|
||||
}
|
||||
}
|
||||
|
||||
for (let i of range(0, 10, 2)) {
|
||||
for (const i of range(0, 10, 2)) {
|
||||
console.log(i); // 0, 2, 4, 6, 8
|
||||
}
|
||||
|
||||
```
|
||||
|
||||
**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-generator-function-definitions)
|
||||
**Documentation:** [link](https://tc39.github.io/ecma262/#sec-generator-function-definitions)
|
||||
|
||||
**Discussion Notes / Link to Thread:**
|
||||
|
||||
@ -861,15 +859,15 @@ within the collection.
|
||||
**Usage Example:**
|
||||
|
||||
```js
|
||||
var key = {};
|
||||
var weakmap = new WeakMap();
|
||||
const key = {};
|
||||
const weakmap = new WeakMap();
|
||||
|
||||
weakmap.set(key, 123);
|
||||
|
||||
weakmap.has(key) && weakmap.get(key) === 123; // true
|
||||
```
|
||||
|
||||
**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-weakmap-objects)
|
||||
**Documentation:** [link](https://tc39.github.io/ecma262/#sec-weakmap-objects)
|
||||
|
||||
**Discussion Notes / Link to Thread:**
|
||||
|
||||
@ -883,8 +881,8 @@ within the collection.
|
||||
**Usage Example:**
|
||||
|
||||
```js
|
||||
var obj1 = {};
|
||||
var weakset = new WeakSet();
|
||||
const obj1 = {};
|
||||
const weakset = new WeakSet();
|
||||
|
||||
weakset.add(obj1);
|
||||
weakset.add(obj1);
|
||||
@ -892,7 +890,7 @@ weakset.add(obj1);
|
||||
weakset.has(obj1); // true
|
||||
```
|
||||
|
||||
**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-weakset-objects)
|
||||
**Documentation:** [link](https://tc39.github.io/ecma262/#sec-weakset-objects)
|
||||
|
||||
**Discussion Notes / Link to Thread:**
|
||||
|
||||
@ -911,7 +909,7 @@ new UInt8ClampedArray();
|
||||
// ... You get the idea. Click on the Documentation link below to see all.
|
||||
```
|
||||
|
||||
**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-typedarray-objects)
|
||||
**Documentation:** [link](https://tc39.github.io/ecma262/#sec-typedarray-objects)
|
||||
|
||||
**Discussion Notes / Link to Thread:**
|
||||
|
||||
@ -924,7 +922,7 @@ Hooking into runtime-level object meta-operations.
|
||||
**Usage Example:**
|
||||
|
||||
```js
|
||||
var keyTracker = new Proxy({}, {
|
||||
const keyTracker = new Proxy({}, {
|
||||
keysCreated: 0,
|
||||
|
||||
get (receiver, key) {
|
||||
@ -943,7 +941,7 @@ keyTracker.key1; // 'key already exists'
|
||||
keyTracker.key2; // '2 keys created!'
|
||||
```
|
||||
|
||||
**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-proxy-object-internal-methods-and-internal-slots)
|
||||
**Documentation:** [link](https://tc39.github.io/ecma262/#sec-proxy-object-internal-methods-and-internal-slots)
|
||||
|
||||
**Discussion Notes / Link to Thread:**
|
||||
|
||||
@ -956,13 +954,13 @@ Make calls corresponding to the object meta-operations.
|
||||
**Usage Example:**
|
||||
|
||||
```js
|
||||
let obj = {a: 1};
|
||||
const obj = {a: 1};
|
||||
Object.defineProperty(obj, 'b', {value: 2});
|
||||
obj[Symbol('c')] = 3;
|
||||
Reflect.ownKeys(obj); // ['a', 'b', Symbol(c)]
|
||||
```
|
||||
|
||||
**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-reflection)
|
||||
**Documentation:** [link](https://tc39.github.io/ecma262/#sec-reflection)
|
||||
|
||||
**Discussion Notes / Link to Thread:**
|
||||
|
||||
@ -978,7 +976,7 @@ A lot of new Math methods.
|
||||
// See Doc
|
||||
```
|
||||
|
||||
**Documentation:** [link](http://www.ecma-international.org/ecma-262/6.0/#sec-math)
|
||||
**Documentation:** [link](https://tc39.github.io/ecma262/#sec-math)
|
||||
|
||||
**Discussion Notes / Link to Thread:**
|
||||
|
||||
|
||||
Reference in New Issue
Block a user